OFF GRID Rainwater Harvesting Part 4 – solar powered pump

Mount the Board in the Mini Pump House

installing the solar board in the off grid pump house

Then I can mount this on the back wall of the box and connect the battery terminals. I designed this rainwater harvesting system with room for expansion.

attaching board to wall of mini off grid pump house

The 12V pump I have won’t draw a lot of amps so for now a single 100 watt solar panel will work for this system. The roof of the pavilion is sloped to the south and the pump will only be used in the summer months when there’s a lot of sun.

The Solar Panel

installing roof mounting brackets to the solar panel

The kit comes with roof mounting brackets.

installing roof mounting brackets to the solar panel

And they are attached to the panel with nuts and bolts.

taping cardboard to protect and shield the solar panel

To protect the panel while I’m handling it I’ll cut some cardboard and tape it to the face. And this will also prevent any shorts or sparks from the wires if I accidentally cross them. I’m not sure if I needed to do this. But, it can’t hurt.

Mount the Solar Panel

setting the solar panel on the pavilion roof

On the roof of the pavilion I’ll set the panel in place and check that the feet of the brackets sit flat between the ribs.

setting the solar panel on the pavilion roof

Looks like it just fits.

setting the solar panel on the pavilion roof

I cut a strip of Eternabond tape and stick it to the roof under the brackets. This should make a water tight seal. And the roofing screws have a rubber washer too.

drilling holes in roof for solar panel controller wires

Now I can drill two holes in the roof for the panel wires.

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feeding wires for solar panel controller
silicone used to seal wires where they penetrate the roof

These wires will run through a water tight housing that I’ll silicone to the roof.

silicone used to seal wires where they penetrate the roof

I’ll tape that in place while the silicone cures. Then connect these wires to the panel and tuck the connectors up underneath.

Running Wire to the Pump House

securing solar panel wires to roof rafters under pavilion

And I can now attach these wires to a rafter with cable ties.

wires attach to terminals on solar board

The wires run down the rafters, along the downspout pipe, across the top of the surround and down and behind the pump house box.

wires attach to terminals on solar board

I added lugs to the ends of these wires and then connect them to the bolt terminals on the board. And it worked out that the wires that came with this kit were exactly the right length to just make it to the terminals.

wires attach to terminals on solar board

I’ll tape up the bare positive terminal. And now I can remove the cardboard from the panel.

Prepare the Water Filter

plumbing and fittings and spin-down filter for drip irrigation system

I have a spin down sediment filter that I will also mount on a board before adding it to the pump house. It has 3/4″ ball valve on either side of the filter and I add 90 degree elbows and a barbed hose adapter. The drip irrigation will have additional finer filters but this spin down will catch anything that makes it past the downspout screen.

plumbing and fittings and spin-down filter for drip irrigation system

And I can mount that in place.

anti-vibration rubber backed plywood for RV DC water pump

Even though these 12 volt pumps have rubber mounting feet they still vibrate a lot. So I though I would try to reduce this with an additional rubber mount. I cut a piece of plywood and glued on a scrap piece of rubber flooring. Then I’ll glue this to the bottom of the pump house box.

anti-vibration rubber backed plywood for RV DC water pump

I’ll use contact cement for this. You can also see from this angle that I added a plywood divider to the box. This was to keep the electrical side separate from the potentially wet pump side. In case I had a leak somewhere. I’ll set the pump in place and screw it to this small piece of plywood. The contact cement worked very well and I don’t think this board is ever coming off.

Secure the 12V DC Water Pump

anti-vibration rubber backed plywood for RV DC water pump

The spin down sediment filter has a valve at the bottom so you can quickly remove some of the debris that builds up. I’ll drill a hole through the box and connect a half inch house for this sediment to drain.

connecting RV DC water pump inlet to line from rainwater tank

A black 3/4″ water line runs in to the box from the bulkhead float fitting on the tank and is connected to the barbed fitting on the filter assembly.

connecting RV DC water pump inlet to line from rainwater tank

And the outlet of the filter to the inlet of the pump with a clear braided hose. And another clear hose to the outlet side of the pump.

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